Looks like SB has a set, but I can't figure out why he wouldn't lead turn, unless he expects you to bet and intends to check raise again. I think your line is good actually. He could flip AK here too, maybe KQ/KJ/KT. Maybe even a busted draw. I think turn check is good for pot control, and I have a hard time folding top two on this board....had he led turn I would have been out of there....